Spasticity following traumatic spinal cord injury frequently interferes with functional skills, can cause painful spasms or can produce contractures in affected individuals. Oral medications are prescribed by physicians to reduce spasticity when one or more of these complications occur. The response to treatment is often disappointing. Clinical studies evaluating the effectiveness of medications have lacked a reliable, valid independent measure of spasticity to assess treatment effect. A reliable and valid spasticity measurement device has been developed which imposes sinusoidal oscillations from 3 to 12 Hz. at the ankle joint, evoking spastic reflex muscle contractions of the anterior and posterior compartment muscles of the leg. Torque and angular displacement measurements taken by the device are converted by Fourier transformation to measures of resistance to passive ankle motion called viscous and elastic stiffness. The pathlength of the curve produced by plotting viscous versus elastic stiffness for the 10 frequencies of oscillation tested (Nyquist Plot) gives an overall reflex gain measurement. Surface EMG activity is monitored from the anterior tibialis and medial gastrocnemius muscles to verify the reflex response from the sinusoidal oscillation stimulus. Reflex gain values obtained from the spasticity measurement device will be utilized as the primary '.dependent measurement of spasticity for the proposed protocols. Clinical examination for signs of spasticity and the Timed Test of Patient Mobility will also be performed as additional -dependent measures. Project years 1 through 5 will evaluate the effectiveness of the antispasticity medications: baclofen, diazepam, dantrolene sodium, clonidine and a combination of the two best drugs determined from the previous cohorts. One cohort will be tested per year. 12 spastic spinal cord injured subjects will be tested in each cohort utilizing a double blind crossover alternate baseline/intervention research design. Two different active medications will be tested against each other and placebo in each cohort. The data will be analyzed by a repeated measures ANOVA. Individual subject treatment response will be analyzed by single-case design statistics. The project will provide improved guidelines for oral medication treatment of spasticity resulting from traumatic spinal cord injury and will establish the spasticity measurement device and the Timed Test of Patient Mobility as reliable and valid measures for treatment effects of antispasticity therapy.